1. Field of the Invention:
The present invention pertains to the preparation of glycoside products by the acid catalyzed reaction of an alcohol reactant and a saccharide reactant. More particularly, the invention is a process for the preparation of glycoside products in a two phase system comprising a liquid phase and a solid phase containing saccharide reactant.
2. Statement of Related Art:
Glycoside products such as alkyl or alkenyl polyglycosides have been known for many years. The materials have not achieved outstanding commercial success because the products generally had a dark color and a low degree of polymerization. In the manufacture of glycoside products from water-soluble monosaccharide and polysaccharide starting materials such as glucose, maltose, sucrose, xylose, lactose and the like by the acid catalyzed reaction with an alcohol reactant such as ethylhexyl alcohol, octyl alcohol, decyl alcohol, dodecyl alcohol, hexadecyl alcohol and the like, it has generally been the practice to introduce the saccharide reactant into the reaction mixture in an amount which would dissolve in the liquid phase and would be completely reacted during the process so that no solid or undissolved phase containing the saccharide reactant remained in the reaction mixture. It was believed necessary not to have a large excess of solid or undissolved phase, containing the saccharide reactant, present during the process and especially where the reaction had proceeded to the point where recovery of the glycoside product was required.
Many processes are known in the art for preparing the glycoside products of the present invention by the reaction of an alcohol and a saccharide reactant. The processes generally utilize solubilizing agents to maintain all of the saccharide reactant in solution during the process or carry out the reaction to the point that no undissolved saccharide reactant remains at the end of the reaction portion of the process.
U.S. Pat. No. 3,598,865 to Lew (Aug. 10, 1971) utilizes a latent solvent to dissolve the saccharide reactant and provide a homogeneous mixture with the alcohol reactant.
U.S. Pat. No. 3,707,535 to Lew (Dec. 26, 1972) discloses the use of a solvent to aid in solubilizing the saccharide reactant.
U.S. Pat. No. 3,974,138 to Lew (Aug. 10, 1976) controls the ratio of alcohol to saccharide so that the product solution produced by the process is clear and contains no undissolved saccharide reactant.
European patent publication 96,917 to Farris Dec. 28, 1983) discloses the incremental addition of the saccharide reactant to the reaction mixture so that no solid phase is present.
European patent publication 106,743.5 (Jan. 13, 1988) discloses adding a sufficient amount of butyl oligoglycoside to the reaction mixture so that a homogeneous reaction mixture is formed.
Glycoside products can be prepared by reacting a long chain alcohol with a saccharide reactant (e.g., a monosaccharide or a material hydrolyzable to a monosaccharide) at an elevated temperature in the presence of an acid catalyst by processes such as disclosed for example, U.S. Pat. No. 3,219,656 to Boettner (issued Nov. 23, 1965); U.S. Pat. No. 3,547,828 to Mansfield et al. (issued Dec. 15, 1970); U.S. Pat. No. 3,772,269 to Lew (issued Nov. 13, 1973); U.S. Pat. No. 3,839,318 to Mansfield (issued Oct. 1, 1974); U.S. Pat. No. 4,349,669 to Klahr (issued Sept. 14, 1982); U.S. Pat. No. 4,393,203 to Mao et al. (issued July 12, 1983); U.S. Pat. No. 4,472,170 to Hellyer (issued Sept. 18, 1984); U.S. Pat. No. 4,510,306 to Langdon (issued April 9, 1985); U.S. Pat. No. 4,597,770 to Forand et al. (issued July 1, 1986; U.S. Pat. No. 4,704,453 to Lorenz et al. (issued Nov. 3, 1987); U.S. Pat. No. 4,713,447 to Letton (issued Dec. 15, 1987); published European Application No. 83302002.7 (EPO Publication No. 0092355; Vander Burgh et al; published Oct. 26, 1983); published European Application No. 83200771.0 (EPO Publication No. 0096917; Farris; published Dec. 28, 1983); and published European Application No. 84303874.6 (EPO Publication 0132043; Davis et al; published Jan. 23, 1985).